The check valve prevents the backflow of exhaust gases into the air injection system. The check valve closes when exhaust gas pressure in exhaust manifold exceeds pressure delivered by pump. This occurs when air pump by-passes at high speeds, air delivery is switched to catalytic converter, air is diverted to atmosphere or air cleaner, or air pump malfunctions.
Contents
Wiring diagrams Section: Theory & Operation- Introduction
- Mass Airflow (MAF)
- Speed Density
- Computerized Engine Controls
- Powertrain Control Module (PCM)
- Arithmetic Logic Unit (Alu)
- Central Processing Unit (Cpu)
- Power Supply
- Memories
- Input Devices
- A/c Request Signal
- A/c Pressure Sensor
- A/c Pressure Switches
- A/c Temperature Sensors
- Battery Voltage
- Brake Switch Feedback
- Camshaft Position Sensor
- Crankshaft Position (Ckp) Sensor
- Engine Coolant Temperature (ECT) Sensor
- Engine Coolant Level Switch
- Engine Oil Level Switch
- Fuel Level Sensor
- Fuel Pump Feedback
- Fuel Tank Vapor Pressure Sensor
- Gear Switches
- Generator "L" Light Circuit
- Generator "F" Field Circuit
- Ignition/crank Signal
- Intake Air Temperature (IAT) Sensor
- Knock Sensor
- Manifold Absolute Pressure (MAP) Sensor
- Mass Airflow (MAF) Sensor
- Oxygen Sensor (O2S)
- Park/neutral Position (Pnp) Switch
- Power Steering Pressure (Psp) Switch
- RPM Reference Signal
- Throttle Position (Tp) Sensor
- Throttle Position Switch
- Transmission Fluid Temperature Sensor
- Transmission Range Switch
- Vehicle Speed Sensor (Vss)
- Output Signals
- A/c Compressor Clutch
- Air Injection System
- Canister Purge Control Solenoid
- Coil-Near-Plug (Cnp) Ignition
- Cooling Fan Relay
- Digital EGR Valve
- Direct Ignition System (Dis)
- EGR Control Solenoid
- Electronic Variable Orifice (Evo) Actuator
- Fuel Injectors
- Fuel Pump & Fuel Pump Relay
- Hot Light or Coolant Temperature (Temp) Light
- Idle Air Control (Iac) Valve
- Linear EGR Valve
- Knock Sensor Operation
- Malfunction Indicator Light (MIL)
- Self-Diagnostics
- Serial Data
- Shift Light
- Shift Solenoids (Electronically-Controlled Auto Transmission)
- Throttle Actuator
- Torque Converter Clutch
- Fuel Pump
- Fuel Pump Relay
- Fuel Pressure Regulator
- Fuel Control
- Open Loop
- Closed Loop
- Battery Voltage Correction
- Fuel Cut-Off
- Multiport Fuel Injection (Mfi)
- Sequential Fuel Injection (Sfi)
- Idle Speed
- Idle Air Control Valve
- Ignition System
- Ignition Timing Advance
- Emission Systems
- Air Pump (Electric)
- Check Valve
- Electric Air Pump Relay
- Three-Way-Catalytic (Twc) Converter
- Exhaust Gas Recirculation (EGR)
- Digital EGR System
- Linear EGR System
- Negative Backpressure EGR Valve
- Evaporative Emission Control
- Carbon Canister
- Canister Purge Control Valve
- Tank Pressure Control Valve
- Positive Crankcase Ventilation (PCV)
- Self-Diagnostic System
- Miscellaneous Controls
- Electric Cooling Fan
- Hot Light or Coolant Temperature Light
- Torque Converter Clutch (Non-Electronic Transmission)
- Torque Converter Clutch (Electronic Transmission)
- Electronic Transmission
- Abbreviations
- Accessory Drive Belts
- Adjustments
- Airbag
- Anti-Lock/traction Control
- Application
- Automatic HVAC System
- Automatic Trans
- Axle Shafts
- Basic Trouble Shooting
- Body, Cab Control Systems
- Brakes
- Charging System
- Check Lists
- Computer Relearn
- Cooling Fan
- Cruise Control Systems
- Diagnostic Connector Locations
- Door Locks & Anti-Theft Systems
- Drive Cycles
- Driveline/axles
- DTC Index
- Electrical
- Electrical Component Locations
- Electronic Suspension
- Emission Applications
- Engine
- Engine Performance
- Fuses & Circuit Breakers
- Gauges & Instrument Panels
- General Servicing - All Makes
- Headlights
- Heated Glass/defoggers
- Identification
- Manual & Power Steering
- MAP Guidelines
- Mechanical
- Mechanical - Hydraulic
- Memory Modules
- Metric Conversions
- Mirrors
- Mode 6
- Procedures
- Removal & Installation
- Reset Procedures
- Restraints
- Rpo Codes
- Seats
- Sensor Range Charts
- Specifications
- Starter
- Steering
- Steering Column
- Steering Column Switches
- Sun Roof/t-Top/convertible Top
- Suspension Front
- Suspension Rear
- Testing & Diagnostics
- Theory & Operation
- Traction Control Disable
- Transmission
- Wheel Alignment
- Windows
- Wiper/washer Systems
- Wiring Diagrams - Engine Performance